The present invention relates generally to storage systems and, more particularly, to selecting an interface by queue and workload for storage operation.
Storage subsystem provides different characteristic interfaces (I/Fs) for storage management, and the I/Fs' characteristics are changed based on condition of I/F processing and the queue of the I/Fs. It is hard to select an I/F efficiently. For example, serial operation I/F (e.g., RMLIB API) is liner order time by the number of storage operations (e.g., attach/detach LUN operations). The slope of liner is changed by the storage's queue length for storage operation batch operation I/F (e.g., RMI API), and it is almost flat performance for a set of storage operations even regardless of the number of storage operations. The intercept of the flat liner is changed by the condition of the SerVice Processor or SVP (update<normal<refresh). Therefore, the user or the system cannot select the appropriate I/F.
One example of in-band storage management I/F, RMLIB, is described in U.S. Patent Application Publication No. 2002/0143903. In that disclosure, the storage system 30 may implement one or more command devices, the agent 29 may be equal to the operation API (RMLIB), and the one or more command devices may be functionally equal to command devices (CMs or CMD in this disclosure). The agent 29 is able to provide an application program interface (API) or a command line interface (CLI) for use in providing instructions for coupling operations to logical units (LUs) in the storage system 30. That disclosure does not teach a queue for requests on CMD. However, it is necessary to process requests from several hosts. The I/F provides capabilities to attach LUN to volume, detach LUN from volume, and to provide copy operation. Examples of the capabilities of attach and detach operations are found in U.S. Pat. No. 7,197,609.
One example of out-band storage interface RMI on SVP is described in U.S. Pat. No. 7,512,888. In that disclosure, FIG. 9 shows RMI server 40h which provides I/F to control from another management server. The configuration of storage is taught in the prior art, and an example of the refresh operation is described in U.S. Patent Application Publication No. 2004/0030730. That disclosure does not teach a batch operation. For example, the management software sends a set of storage operations to storage subsystems. Then each storage subsystem executes it once. However, it is a considerable technical operation. The behavior of I/F, especially the operation speed, is also not disclosed well.